books.google.ca - For colonial administrators and the Belgian banks, the Belgian Congo was an immensely rich source of raw materials; diamonds, gold, manganese, oils, nuts, tobacco, peanuts, etc. One of the major forms of exploitation of the Congo was the effort to set up mining companies and to force Africans to work...http://books.google.ca/books/about/A_Working_Class_in_the_Making.html?id=83Oo5-PT45cC&utm_source=gb-gplus-shareA Working Class in the Making